Pauley Perrette has had a severe allergic reaction to hair dye, and wants to warn others of the symptoms.

Perrette is most known for her role on CBS' procedural NCIS, where she plays a gothic forensic scientist, Abby Sciuto. The actress has been dying her hair black since her first appearance on the show in 2003 however, her most recent dye-job did not go as planned.

The actress has been having allergic symptoms with the hair dye for the past year, so it was only a matter of time before the product caused a severe reaction.

“This was me at hospital today and it got worse,” Perrette wrote on her Twitter account, displaying a picture of her very swollen face.

The natural blonde recently posted on Twitter to warn others of the symptoms, claiming the allergic reaction can easily be fatal if it is not treated right away, says NY Daily News.